👉 Ostracoberycids are a group of extinct, small to medium-sized mammals that lived during the late Cretaceous period in North America and Europe. These creatures were characterized by their elongated bodies, short limbs, and small brains. They had a distinctive skull with large horns on the top of the skull, which served as a defense mechanism against predators. Ostracoberycids are considered to be the ancestors of modern mammals and play a crucial role in understanding the evolution of verte